An outbreak of bluetongue in sheep in the Sudan

An outbreak of bluetongue and the first isolation of the virus in the Sudan are reported. The disease occurred in sheep stressed by walking for five days when biting arthropods were prevalent. Estimates of the morbidity and mortality rates ranged from about 30 per cent and 2 per cent respectively in adult sheep to around 80 per cent and 100 per cent respectively in lambs. The virus was isolated by the inoculation of suckling mice and embryonated eggs with whole blood from febrile sheep. In a gel precipitation test it reacted with specific antiserum to type 10 BT8 strain. No other agent was isolated. Given the relatively mild nature of bluetongue in indigenous sheep, it is believed that the long walking stress coupled with exposure to sunlight might have aggravated the severity of the disease in this particular outbreak.